client lib - new binding

packages/builder/src/builderStore/uuid.js

@@ -1,5 +1,7 @@
 export function uuid() {
-  return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, c => {
+  // always want to make this start with a letter, as this makes it
+  // easier to use with mustache bindings in the client
+  return "cxxxxxxxxxxxx4xxxyxxxxxxxxxxxxxxx".replace(/[xy]/g, c => {
     const r = (Math.random() * 16) | 0,
       v = c == "x" ? r : (r & 0x3) | 0x8
     return v.toString(16)

packages/client/package.json

@@ -21,28 +21,24 @@
       "\\.(css|less|sass|scss)$": "identity-obj-proxy"
     },
     "moduleFileExtensions": [
-      "js"
+      "js",
+      "svelte"
     ],
     "moduleDirectories": [
       "node_modules"
     ],
     "transform": {
-      "^.+js$": "babel-jest"
+      "^.+js$": "babel-jest",
+      "^.+.svelte$": "svelte-jester"
     },
     "transformIgnorePatterns": [
       "/node_modules/(?!svelte).+\\.js$"
     ]
   },
   "dependencies": {
-    "@nx-js/compiler-util": "^2.0.0",
-    "bcryptjs": "^2.4.3",
     "deep-equal": "^2.0.1",
-    "lodash": "^4.17.15",
-    "lunr": "^2.3.5",
     "mustache": "^4.0.1",
-    "regexparam": "^1.3.0",
-    "shortid": "^2.2.8",
-    "svelte": "^3.9.2"
+    "regexparam": "^1.3.0"
   },
   "devDependencies": {
     "@babel/core": "^7.5.5",
@@ -58,7 +54,9 @@
     "rollup-plugin-node-builtins": "^2.1.2",
     "rollup-plugin-node-globals": "^1.4.0",
     "rollup-plugin-node-resolve": "^5.2.0",
-    "rollup-plugin-terser": "^4.0.4"
+    "rollup-plugin-terser": "^4.0.4",
+    "svelte": "3.23.x",
+    "svelte-jester": "^1.0.6"
   },
   "gitHead": "e4e053cb6ff9a0ddc7115b44ccaa24b8ec41fb9a"
 }

packages/client/rollup.config.js

@@ -3,74 +3,6 @@ import commonjs from "rollup-plugin-commonjs"
 import builtins from "rollup-plugin-node-builtins"
 import nodeglobals from "rollup-plugin-node-globals"
 
-const lodash_fp_exports = [
-  "find",
-  "compose",
-  "isUndefined",
-  "split",
-  "max",
-  "last",
-  "union",
-  "reduce",
-  "isObject",
-  "cloneDeep",
-  "some",
-  "isArray",
-  "map",
-  "filter",
-  "keys",
-  "isFunction",
-  "isEmpty",
-  "countBy",
-  "join",
-  "includes",
-  "flatten",
-  "constant",
-  "first",
-  "intersection",
-  "take",
-  "has",
-  "mapValues",
-  "isString",
-  "isBoolean",
-  "isNull",
-  "isNumber",
-  "isObjectLike",
-  "isDate",
-  "clone",
-  "values",
-  "keyBy",
-  "isNaN",
-  "isInteger",
-  "toNumber",
-]
-
-const lodash_exports = [
-  "flow",
-  "head",
-  "find",
-  "each",
-  "tail",
-  "findIndex",
-  "startsWith",
-  "dropRight",
-  "takeRight",
-  "trim",
-  "split",
-  "replace",
-  "merge",
-  "assign",
-]
-
-const coreExternal = [
-  "lodash",
-  "lodash/fp",
-  "lunr",
-  "safe-buffer",
-  "shortid",
-  "@nx-js/compiler-util",
-]
-
 export default {
   input: "src/index.js",
   output: [
@@ -90,17 +22,8 @@ export default {
     resolve({
       preferBuiltins: true,
       browser: true,
-      dedupe: importee => {
-        return coreExternal.includes(importee)
-      },
-    }),
-    commonjs({
-      namedExports: {
-        "lodash/fp": lodash_fp_exports,
-        lodash: lodash_exports,
-        shortid: ["generate"],
-      },
     }),
+    commonjs(),
     builtins(),
     nodeglobals(),
   ],

packages/client/src/api/authenticate.js

@@ -1,3 +1,5 @@
+import appStore from "../state/store"
+
 export const USER_STATE_PATH = "_bbuser"
 
 export const authenticate = api => async ({ username, password }) => {
@@ -17,6 +19,10 @@ export const authenticate = api => async ({ username, password }) => {
   })
 
   // set user even if error - so it is defined at least
-  api.setState(USER_STATE_PATH, user)
+  appStore.update(s => {
+    s[USER_STATE_PATH] = user
+    return s
+  })
+
   localStorage.setItem("budibase:user", JSON.stringify(user))
 }

packages/client/src/api/index.js

@@ -1,62 +1,59 @@
 import { authenticate } from "./authenticate"
 import { triggerWorkflow } from "./workflow"
+import appStore from "../state/store"
 
-export const createApi = ({ setState, getState }) => {
-  const apiCall = method => async ({ url, body }) => {
-    const response = await fetch(url, {
-      method: method,
-      headers: {
-        "Content-Type": "application/json",
-      },
-      body: body && JSON.stringify(body),
-      credentials: "same-origin",
-    })
+const apiCall = method => async ({ url, body }) => {
+  const response = await fetch(url, {
+    method: method,
+    headers: {
+      "Content-Type": "application/json",
+    },
+    body: body && JSON.stringify(body),
+    credentials: "same-origin",
+  })
 
-    switch (response.status) {
-      case 200:
+  switch (response.status) {
+    case 200:
+      return response.json()
+    case 404:
+      return error(`${url} Not found`)
+    case 400:
+      return error(`${url} Bad Request`)
+    case 403:
+      return error(`${url} Forbidden`)
+    default:
+      if (response.status >= 200 && response.status < 400) {
         return response.json()
-      case 404:
-        return error(`${url} Not found`)
-      case 400:
-        return error(`${url} Bad Request`)
-      case 403:
-        return error(`${url} Forbidden`)
-      default:
-        if (response.status >= 200 && response.status < 400) {
-          return response.json()
-        }
+      }
 
-        return error(`${url} - ${response.statusText}`)
-    }
-  }
-
-  const post = apiCall("POST")
-  const get = apiCall("GET")
-  const patch = apiCall("PATCH")
-  const del = apiCall("DELETE")
-
-  const ERROR_MEMBER = "##error"
-  const error = message => {
-    const err = { [ERROR_MEMBER]: message }
-    setState("##error_message", message)
-    return err
-  }
-
-  const isSuccess = obj => !obj || !obj[ERROR_MEMBER]
-
-  const apiOpts = {
-    setState,
-    getState,
-    isSuccess,
-    error,
-    post,
-    get,
-    patch,
-    delete: del,
-  }
-
-  return {
-    authenticate: authenticate(apiOpts),
-    triggerWorkflow: triggerWorkflow(apiOpts),
+      return error(`${url} - ${response.statusText}`)
   }
 }
+
+const post = apiCall("POST")
+const get = apiCall("GET")
+const patch = apiCall("PATCH")
+const del = apiCall("DELETE")
+
+const ERROR_MEMBER = "##error"
+const error = message => {
+  const err = { [ERROR_MEMBER]: message }
+  appStore.update(s => s["##error_message"], message)
+  return err
+}
+
+const isSuccess = obj => !obj || !obj[ERROR_MEMBER]
+
+const apiOpts = {
+  isSuccess,
+  error,
+  post,
+  get,
+  patch,
+  delete: del,
+}
+
+export default {
+  authenticate: authenticate(apiOpts),
+  triggerWorkflow: triggerWorkflow(apiOpts),
+}

packages/client/src/api/workflow/actions.js

@@ -1,16 +1,6 @@
-import { setState } from "../../state/setState"
-
 const delay = ms => new Promise(resolve => setTimeout(resolve, ms))
 
 export default {
-  SET_STATE: ({ context, args, id }) => {
-    setState(...Object.values(args))
-    context = {
-      ...context,
-      [id]: args,
-    }
-    return context
-  },
   NAVIGATE: () => {
     // TODO client navigation
   },

packages/client/src/api/workflow/index.js

@@ -1,6 +1,5 @@
-import { get } from "svelte/store"
 import mustache from "mustache"
-import { appStore } from "../../state/store"
+import appStore from "../../state/store"
 import Orchestrator from "./orchestrator"
 import clientActions from "./actions"
 
@@ -20,7 +19,7 @@ export const clientStrategy = ({ api }) => ({
       // Render the string with values from the workflow context and state
       mappedArgs[arg] = mustache.render(argValue, {
         context: this.context,
-        state: get(appStore),
+        state: appStore.get(),
       })
     }
 

packages/client/src/render/attachChildren.js

@@ -1,7 +1,7 @@
-import { split, last, compose } from "lodash/fp"
 import { prepareRenderComponent } from "./prepareRenderComponent"
 import { isScreenSlot } from "./builtinComponents"
 import deepEqual from "deep-equal"
+import appStore from "../state/store"
 
 export const attachChildren = initialiseOpts => (htmlElement, options) => {
   const {
@@ -30,11 +30,28 @@ export const attachChildren = initialiseOpts => (htmlElement, options) => {
     }
   }
 
-  const contextArray = Array.isArray(context) ? context : [context]
+  const contextStoreKeys = []
+
+  // create new context if supplied
+  if (context) {
+    let childIndex = 0
+    // if context is an array,  map to new structure
+    const contextArray = Array.isArray(context) ? context : [context]
+    for (let ctx of contextArray) {
+      const key = appStore.create(
+        ctx,
+        treeNode.props._id,
+        childIndex,
+        treeNode.contextStoreKey
+      )
+      contextStoreKeys.push(key)
+      childIndex++
+    }
+  }
 
   const childNodes = []
 
-  for (let context of contextArray) {
+  const createChildNodes = contextStoreKey => {
     for (let childProps of treeNode.props._children) {
       const { componentName, libName } = splitName(childProps._component)
 
@@ -42,25 +59,33 @@ export const attachChildren = initialiseOpts => (htmlElement, options) => {
 
       const ComponentConstructor = componentLibraries[libName][componentName]
 
-      const prepareNodes = ctx => {
-        const childNodesThisIteration = prepareRenderComponent({
-          props: childProps,
-          parentNode: treeNode,
-          ComponentConstructor,
-          htmlElement,
-          anchor,
-          context: ctx,
-        })
+      const childNode = prepareRenderComponent({
+        props: childProps,
+        parentNode: treeNode,
+        ComponentConstructor,
+        htmlElement,
+        anchor,
+        // in same context as parent, unless a new one was supplied
+        contextStoreKey,
+      })
 
-        for (let childNode of childNodesThisIteration) {
-          childNodes.push(childNode)
-        }
-      }
-
-      prepareNodes(context)
+      childNodes.push(childNode)
     }
   }
 
+  if (context) {
+    // if new context(s) is supplied, then create nodes
+    // with keys to new context stores
+    for (let contextStoreKey of contextStoreKeys) {
+      createChildNodes(contextStoreKey)
+    }
+  } else {
+    // otherwise, use same context store as parent
+    // which maybe undefined (therfor using the root state)
+    createChildNodes(treeNode.contextStoreKey)
+  }
+
+  // if everything is equal, then don't re-render
   if (areTreeNodesEqual(treeNode.children, childNodes)) return treeNode.children
 
   for (let node of childNodes) {
@@ -81,9 +106,9 @@ export const attachChildren = initialiseOpts => (htmlElement, options) => {
 }
 
 const splitName = fullname => {
-  const getComponentName = compose(last, split("/"))
+  const nameParts = fullname.split("/")
 
-  const componentName = getComponentName(fullname)
+  const componentName = nameParts[nameParts.length - 1]
 
   const libName = fullname.substring(
     0,

packages/client/src/render/prepareRenderComponent.js

@@ -1,5 +1,6 @@
-import { appStore } from "../state/store"
 import mustache from "mustache"
+import appStore from "../state/store"
+import hasBinding from "../state/hasBinding"
 
 export const prepareRenderComponent = ({
   ComponentConstructor,
@@ -7,62 +8,54 @@ export const prepareRenderComponent = ({
   anchor,
   props,
   parentNode,
-  context,
+  contextStoreKey,
 }) => {
-  const parentContext = (parentNode && parentNode.context) || {}
+  const thisNode = createTreeNode()
+  thisNode.parentNode = parentNode
+  thisNode.props = props
+  thisNode.contextStoreKey = contextStoreKey
 
-  let nodesToRender = []
-  const createNodeAndRender = () => {
-    let componentContext = parentContext
-    if (context) {
-      componentContext = { ...context }
-      componentContext.$parent = parentContext
+  // the treeNode is first created (above), and then this
+  // render method is add. The treeNode is returned, and
+  // render is called later (in attachChildren)
+  thisNode.render = initialProps => {
+    thisNode.component = new ComponentConstructor({
+      target: htmlElement,
+      props: initialProps,
+      hydrate: false,
+      anchor,
+    })
+
+    // finds the root element of the component, which was created by the contructor above
+    // we use this later to attach a className to. This is how styles
+    // are applied by the builder
+    thisNode.rootElement = htmlElement.children[htmlElement.children.length - 1]
+
+    let [componentName] = props._component.match(/[a-z]*$/)
+    if (props._id && thisNode.rootElement) {
+      thisNode.rootElement.classList.add(`${componentName}-${props._id}`)
     }
 
-    const thisNode = createTreeNode()
-    thisNode.context = componentContext
-    thisNode.parentNode = parentNode
-    thisNode.props = props
-    nodesToRender.push(thisNode)
-
-    thisNode.render = initialProps => {
-      thisNode.component = new ComponentConstructor({
-        target: htmlElement,
-        props: initialProps,
-        hydrate: false,
-        anchor,
-      })
-      thisNode.rootElement =
-        htmlElement.children[htmlElement.children.length - 1]
-
-      let [componentName] = props._component.match(/[a-z]*$/)
-      if (props._id && thisNode.rootElement) {
-        thisNode.rootElement.classList.add(`${componentName}-${props._id}`)
-      }
-
-      // make this node listen to the store
-      if (thisNode.stateBound) {
-        const unsubscribe = appStore.subscribe(state => {
-          const storeBoundProps = { ...initialProps._bb.props }
-          for (let prop in storeBoundProps) {
-            const propValue = storeBoundProps[prop]
-            if (typeof propValue === "string") {
-              storeBoundProps[prop] = mustache.render(propValue, {
-                state,
-                context: componentContext,
-              })
-            }
+    // make this node listen to the store
+    if (thisNode.stateBound) {
+      const unsubscribe = appStore.subscribe(state => {
+        const storeBoundProps = Object.keys(initialProps._bb.props).filter(p =>
+          hasBinding(initialProps._bb.props[p])
+        )
+        if (storeBoundProps.length > 0) {
+          const toSet = {}
+          for (let prop of storeBoundProps) {
+            const propValue = initialProps._bb.props[prop]
+            toSet[prop] = mustache.render(propValue, state)
           }
-          thisNode.component.$set(storeBoundProps)
-        })
-        thisNode.unsubscribe = unsubscribe
-      }
+          thisNode.component.$set(toSet)
+        }
+      }, thisNode.contextStoreKey)
+      thisNode.unsubscribe = unsubscribe
     }
   }
 
-  createNodeAndRender()
-
-  return nodesToRender
+  return thisNode
 }
 
 export const createTreeNode = () => ({

packages/client/src/render/screenRouter.js

@@ -1,5 +1,5 @@
 import regexparam from "regexparam"
-import { appStore } from "../state/store"
+import appStore from "../state/store"
 import { parseAppIdFromCookie } from "./getAppId"
 
 export const screenRouter = ({ screens, onScreenSelected, window }) => {

packages/client/src/state/bbComponentApi.js

@@ -1,11 +1,9 @@
-import { setState } from "./setState"
+import setBindableComponentProp from "./setBindableComponentProp"
 import { attachChildren } from "../render/attachChildren"
-import { getContext, setContext } from "./getSetContext"
 
 export const trimSlash = str => str.replace(/^\/+|\/+$/g, "")
 
 export const bbFactory = ({
-  store,
   componentLibraries,
   onScreenSlotRendered,
   getCurrentState,
@@ -45,13 +43,9 @@ export const bbFactory = ({
 
     return {
       attachChildren: attachChildren(attachParams),
-      context: treeNode.context,
       props: treeNode.props,
       call: safeCallEvent,
-      setState,
-      getContext: getContext(treeNode),
-      setContext: setContext(treeNode),
-      store: store,
+      setBinding: setBindableComponentProp(treeNode),
       api,
       parent,
       // these parameters are populated by screenRouter

packages/client/src/state/eventHandlers.js

@@ -1,8 +1,4 @@
-import { setState } from "./setState"
-import { getState } from "./getState"
-import { isArray, isUndefined } from "lodash/fp"
-
-import { createApi } from "../api"
+import api from "../api"
 
 export const EVENT_TYPE_MEMBER_NAME = "##eventHandlerType"
 
@@ -12,21 +8,13 @@ export const eventHandlers = routeTo => {
     parameters,
   })
 
-  const api = createApi({
-    setState,
-    getState: (path, fallback) => getState(path, fallback),
-  })
-
-  const setStateHandler = ({ path, value }) => setState(path, value)
-
   return {
-    "Set State": handler(["path", "value"], setStateHandler),
     "Navigate To": handler(["url"], param => routeTo(param && param.url)),
     "Trigger Workflow": handler(["workflow"], api.triggerWorkflow),
   }
 }
 
 export const isEventType = prop =>
-  isArray(prop) &&
+  Array.isArray(prop) &&
   prop.length > 0 &&
-  !isUndefined(prop[0][EVENT_TYPE_MEMBER_NAME])
+  !prop[0][EVENT_TYPE_MEMBER_NAME] === undefined

packages/client/src/state/getState.js

@@ -1,9 +0,0 @@
-import { get } from "svelte/store"
-import getOr from "lodash/fp/getOr"
-import { appStore } from "./store"
-
-export const getState = (path, fallback) => {
-  if (!path || path.length === 0) return fallback
-
-  return getOr(fallback, path, get(appStore))
-}

packages/client/src/state/hasBinding.js

@@ -0,0 +1 @@
+export default value => typeof value === "string" && value.includes("{{")

packages/client/src/state/setBindableComponentProp.js

@@ -0,0 +1,13 @@
+import appStore from "./store"
+
+export default treeNode => (propName, value) => {
+  if (!propName || propName.length === 0) return
+  if (!treeNode) return
+  const componentId = treeNode.props._id
+
+  appStore.update(state => {
+    state[componentId] = state[componentId] || {}
+    state[componentId][propName] = value
+    return state
+  }, treeNode.contextStoreKey)
+}

packages/client/src/state/setState.js

@@ -1,11 +0,0 @@
-import set from "lodash/fp/set"
-import { appStore } from "./store"
-
-export const setState = (path, value) => {
-  if (!path || path.length === 0) return
-
-  appStore.update(state => {
-    state = set(path, value, state)
-    return state
-  })
-}

packages/client/src/state/stateManager.js

@@ -5,8 +5,8 @@ import {
 } from "./eventHandlers"
 import { bbFactory } from "./bbComponentApi"
 import mustache from "mustache"
-import { get } from "svelte/store"
-import { appStore } from "./store"
+import appStore from "./store"
+import hasBinding from "./hasBinding"
 
 const doNothing = () => {}
 doNothing.isPlaceholder = true
@@ -37,41 +37,34 @@ export const createStateManager = ({
   const getCurrentState = () => currentState
 
   const bb = bbFactory({
-    store: appStore,
     getCurrentState,
     componentLibraries,
     onScreenSlotRendered,
   })
 
-  const setup = _setup({ handlerTypes, getCurrentState, bb, store: appStore })
+  const setup = _setup({ handlerTypes, getCurrentState, bb })
 
   return {
     setup,
     destroy: () => {},
     getCurrentState,
-    store: appStore,
   }
 }
 
-const _setup = ({ handlerTypes, getCurrentState, bb, store }) => node => {
+const _setup = ({ handlerTypes, getCurrentState, bb }) => node => {
   const props = node.props
-  const context = node.context || {}
   const initialProps = { ...props }
-  const currentStoreState = get(appStore)
 
   for (let propName in props) {
     if (isMetaProp(propName)) continue
 
     const propValue = props[propName]
 
-    // A little bit of a hack - won't bind if the string doesn't start with {{
-    const isBound = typeof propValue === "string" && propValue.includes("{{")
+    const isBound = hasBinding(propValue)
 
     if (isBound) {
-      initialProps[propName] = mustache.render(propValue, {
-        state: currentStoreState,
-        context,
-      })
+      const state = appStore.getState(node.contextStoreKey)
+      initialProps[propName] = mustache.render(propValue, state)
 
       if (!node.stateBound) {
         node.stateBound = true
@@ -79,6 +72,7 @@ const _setup = ({ handlerTypes, getCurrentState, bb, store }) => node => {
     }
 
     if (isEventType(propValue)) {
+      const state = appStore.getState(node.contextStoreKey)
       const handlersInfos = []
       for (let event of propValue) {
         const handlerInfo = {
@@ -89,11 +83,7 @@ const _setup = ({ handlerTypes, getCurrentState, bb, store }) => node => {
         const resolvedParams = {}
         for (let paramName in handlerInfo.parameters) {
           const paramValue = handlerInfo.parameters[paramName]
-          resolvedParams[paramName] = () =>
-            mustache.render(paramValue, {
-              state: getCurrentState(),
-              context,
-            })
+          resolvedParams[paramName] = () => mustache.render(paramValue, state)
         }
 
         handlerInfo.parameters = resolvedParams
@@ -113,7 +103,7 @@ const _setup = ({ handlerTypes, getCurrentState, bb, store }) => node => {
     }
   }
 
-  const setup = _setup({ handlerTypes, getCurrentState, bb, store })
+  const setup = _setup({ handlerTypes, getCurrentState, bb })
   initialProps._bb = bb(node, setup)
 
   return initialProps

packages/client/src/state/store.js

@@ -1,9 +1,104 @@
 import { writable } from "svelte/store"
 
-const appStore = writable({})
-appStore.actions = {}
+// we assume that the reference to this state object
+// will remain for the life of the application
+const rootState = {}
+const rootStore = writable(rootState)
+const contextStores = {}
 
-const routerStore = writable({})
-routerStore.actions = {}
+// contextProviderId is the component id that provides the data for the context
+const contextStoreKey = (dataProviderId, childIndex) =>
+  `${dataProviderId}${childIndex >= 0 ? ":" + childIndex : ""}`
 
-export { appStore, routerStore }
+// creates a store for a datacontext (e.g. each item in a list component)
+const create = (data, dataProviderId, childIndex, parentContextStoreId) => {
+  const key = contextStoreKey(dataProviderId, childIndex)
+  const state = { data }
+
+  // add reference to parent state object,
+  // so we can use bindings like state.parent.parent
+  // (if no parent, then parent is rootState )
+  state.parent = parentContextStoreId
+    ? contextStores[parentContextStoreId].state
+    : rootState
+
+  if (!contextStores[key]) {
+    contextStores[key] = {
+      store: writable(state),
+      subscriberCount: 0,
+      state,
+      parentContextStoreId,
+    }
+  }
+  return key
+}
+
+const subscribe = (subscription, storeKey) => {
+  if (!storeKey) {
+    return rootStore.subscribe(subscription)
+  }
+  const contextStore = contextStores[storeKey]
+
+  // we are subscribing to multiple stores,
+  // we dont want to each subscription the first time
+  // as this could repeatedly run $set on the same component
+  // ... which already has its initial properties set properly
+  const ignoreFirstSubscription = () => {
+    let hasRunOnce = false
+    return () => {
+      if (hasRunOnce) subscription(contextStore.state)
+      hasRunOnce = true
+    }
+  }
+
+  const unsubscribes = [rootStore.subscribe(ignoreFirstSubscription())]
+
+  // we subscribe to all stores in the hierarchy
+  const ancestorSubscribe = ctxStore => {
+    // unsubscribe func returned by svelte store
+    const svelteUnsub = ctxStore.store.subscribe(ignoreFirstSubscription())
+
+    // we wrap the svelte unsubscribe, so we can
+    // cleanup stores when they are no longer subscribed to
+    const unsub = () => {
+      ctxStore.subscriberCount = contextStore.subscriberCount - 1
+      // when no subscribers left, we delete the store
+      if (ctxStore.subscriberCount === 0) {
+        delete ctxStore[storeKey]
+      }
+      svelteUnsub()
+    }
+    unsubscribes.push(unsub)
+    if (ctxStore.parentContextStoreId) {
+      ancestorSubscribe(contextStores[ctxStore.parentContextStoreId])
+    }
+  }
+
+  ancestorSubscribe(contextStore)
+
+  // our final unsubscribe function calls unsubscribe on all stores
+  return () => unsubscribes.forEach(u => u())
+}
+
+const findStore = (dataProviderId, childIndex) =>
+  dataProviderId
+    ? contextStores[contextStoreKey(dataProviderId, childIndex)].store
+    : rootStore
+
+const update = (updatefunc, dataProviderId, childIndex) =>
+  findStore(dataProviderId, childIndex).update(updatefunc)
+
+const set = (value, dataProviderId, childIndex) =>
+  findStore(dataProviderId, childIndex).set(value)
+
+const getState = contextStoreKey =>
+  contextStoreKey ? contextStores[contextStoreKey].state : rootState
+
+export default {
+  subscribe,
+  update,
+  set,
+  getState,
+  create,
+  contextStoreKey,
+}

packages/client/tests/binding.spec.js

@@ -0,0 +1,209 @@
+import { load, makePage, makeScreen } from "./testAppDef"
+
+describe("binding", () => {
+
+
+  it("should bind to data in context", async () => {
+    const { dom } = await load(
+      makePage({
+        _component: "testlib/div",
+        _children: [
+          {
+            _component: "##builtin/screenslot",
+            text: "header one",
+          },
+        ],
+      }),
+      [
+        makeScreen("/", {
+          _component: "testlib/list",
+          data: dataArray,
+          _children: [
+            {
+              _component: "testlib/h1",
+              text: "{{data.name}}",
+            }
+          ],
+        }),
+      ]
+    )
+
+    const rootDiv = dom.window.document.body.children[0]
+    expect(rootDiv.children.length).toBe(1)
+
+    const screenRoot = rootDiv.children[0]
+
+    expect(screenRoot.children[0].children.length).toBe(2)
+    expect(screenRoot.children[0].children[0].innerText).toBe(dataArray[0].name)
+    expect(screenRoot.children[0].children[1].innerText).toBe(dataArray[1].name)
+  })
+
+  it("should bind to input in root", async () => {
+    const { dom } = await load(
+      makePage({
+        _component: "testlib/div",
+        _children: [
+          {
+            _component: "##builtin/screenslot",
+            text: "header one",
+          },
+        ],
+      }),
+      [
+        makeScreen("/", {
+          _component: "testlib/div",
+          _children: [
+            {
+              _component: "testlib/h1",
+              text: "{{inputid.value}}",
+            },
+            {
+              _id: "inputid",
+              _component: "testlib/input",
+              value: "hello"
+            }
+          ],
+        }),
+      ]
+    )
+
+    const rootDiv = dom.window.document.body.children[0]
+    expect(rootDiv.children.length).toBe(1)
+
+    const screenRoot = rootDiv.children[0]
+
+    expect(screenRoot.children[0].children.length).toBe(2)
+    expect(screenRoot.children[0].children[0].innerText).toBe("hello")
+
+    // change value of input
+    const input = dom.window.document.getElementsByClassName("input-inputid")[0]
+
+    changeInputValue(dom, input, "new value")
+    expect(screenRoot.children[0].children[0].innerText).toBe("new value")
+
+  })
+
+  it("should bind to input in context", async () => {
+    const { dom } = await load(
+      makePage({
+        _component: "testlib/div",
+        _children: [
+          {
+            _component: "##builtin/screenslot",
+            text: "header one",
+          },
+        ],
+      }),
+      [
+        makeScreen("/", {
+          _component: "testlib/list",
+          data: dataArray,
+          _children: [
+            {
+              _component: "testlib/h1",
+              text: "{{inputid.value}}",
+            },
+            {
+              _id: "inputid",
+              _component: "testlib/input",
+              value: "hello"
+            }
+          ],
+        }),
+      ]
+    )
+
+    const rootDiv = dom.window.document.body.children[0]
+    expect(rootDiv.children.length).toBe(1)
+
+    const screenRoot = rootDiv.children[0]
+    expect(screenRoot.children[0].children.length).toBe(4)
+
+    const firstHeader = screenRoot.children[0].children[0]
+    const firstInput = screenRoot.children[0].children[1]
+    const secondHeader = screenRoot.children[0].children[2]
+    const secondInput = screenRoot.children[0].children[3]
+    
+    expect(firstHeader.innerText).toBe("hello")
+    expect(secondHeader.innerText).toBe("hello")
+
+    changeInputValue(dom, firstInput, "first input value")
+    expect(firstHeader.innerText).toBe("first input value")
+
+    changeInputValue(dom, secondInput, "second input value")
+    expect(secondHeader.innerText).toBe("second input value")
+
+  })
+
+  it("should bind contextual component, to input in root context", async () => {
+    const { dom } = await load(
+      makePage({
+        _component: "testlib/div",
+        _children: [
+          {
+            _component: "##builtin/screenslot",
+            text: "header one",
+          },
+        ],
+      }),
+      [
+        makeScreen("/", {
+          _component: "testlib/div",
+          _children: [
+            {
+              _id: "inputid",
+              _component: "testlib/input",
+              value: "hello"
+            },
+            {
+              _component: "testlib/list",
+              data: dataArray,
+              _children: [
+                {
+                  _component: "testlib/h1",
+                  text: "{{parent.inputid.value}}",
+                },
+              ],
+            }
+          ]
+        }),
+      ]
+    )
+
+    const rootDiv = dom.window.document.body.children[0]
+    expect(rootDiv.children.length).toBe(1)
+
+    const screenRoot = rootDiv.children[0]
+    expect(screenRoot.children[0].children.length).toBe(2)
+
+    const input = screenRoot.children[0].children[0]
+
+    const firstHeader = screenRoot.children[0].children[1].children[0]
+    const secondHeader = screenRoot.children[0].children[1].children[0]
+    
+    expect(firstHeader.innerText).toBe("hello")
+    expect(secondHeader.innerText).toBe("hello")
+
+    changeInputValue(dom, input, "new input value")
+    expect(firstHeader.innerText).toBe("new input value")
+    expect(secondHeader.innerText).toBe("new input value")
+
+  })
+
+  const changeInputValue = (dom, input, newValue) => {
+    var event = new dom.window.Event("change")
+    input.value = newValue
+    input.dispatchEvent(event)
+  }
+
+  const dataArray = [
+    {
+      name: "katherine",
+      age: 30,
+    },
+    {
+      name: "steve",
+      age: 41,
+    },
+  ]
+})

packages/client/tests/initialiseApp.spec.js

@@ -135,4 +135,38 @@ describe("initialiseApp", () => {
     expect(screenRoot.children[0].children[0].innerText).toBe("header one")
     expect(screenRoot.children[0].children[1].innerText).toBe("header two")
   })
+
+  it("should repeat elements that pass an array of contexts", async () => {
+    const { dom } = await load(
+      makePage({
+        _component: "testlib/div",
+        _children: [
+          {
+            _component: "##builtin/screenslot",
+            text: "header one",
+          },
+        ],
+      }),
+      [
+        makeScreen("/", {
+          _component: "testlib/list",
+          data: [1,2,3,4],
+          _children: [
+            {
+              _component: "testlib/h1",
+              text: "header",
+            }
+          ],
+        }),
+      ]
+    )
+
+    const rootDiv = dom.window.document.body.children[0]
+    expect(rootDiv.children.length).toBe(1)
+
+    const screenRoot = rootDiv.children[0]
+
+    expect(screenRoot.children[0].children.length).toBe(4)
+    expect(screenRoot.children[0].children[0].innerText).toBe("header")
+  })
 })

packages/client/tests/testAppDef.js

@@ -194,4 +194,47 @@ const maketestlib = window => ({
     set(opts.props)
     opts.target.appendChild(node)
   },
+
+  list: function(opts) {
+    const node = window.document.createElement("DIV")
+
+    let currentProps = { ...opts.props }
+
+    const set = props => {
+      currentProps = Object.assign(currentProps, props)
+      if (currentProps._children && currentProps._children.length > 0) {
+        currentProps._bb.attachChildren(node, {
+          context: currentProps.data || {},
+        })
+      }
+    }
+
+    this.$destroy = () => opts.target.removeChild(node)
+
+    this.$set = set
+    this._element = node
+    set(opts.props)
+    opts.target.appendChild(node)
+  },
+
+  input: function(opts) {
+    const node = window.document.createElement("INPUT")
+    let currentProps = { ...opts.props }
+
+    const set = props => {
+      currentProps = Object.assign(currentProps, props)
+      opts.props._bb.setBinding("value", props.value)
+    }
+
+    node.addEventListener("change", e => {
+      opts.props._bb.setBinding("value", e.target.value)
+    })
+
+    this.$destroy = () => opts.target.removeChild(node)
+
+    this.$set = set
+    this._element = node
+    set(opts.props)
+    opts.target.appendChild(node)
+  },
 })

packages/client/tests/testComponents/container.svelte

@@ -0,0 +1,16 @@
+<script>
+  export let _bb
+  export let className = ""
+
+  let containerElement
+  let hasLoaded
+
+  $: {
+    if (containerElement) {
+      _bb.attachChildren(containerElement)
+      hasLoaded = true
+    }
+  }
+</script>
+
+<div bind:this={containerElement} class={className} />